understanding nodes as entrypoints?

[clisterX]

Hi, this is a very general question with which I only want to improve my understanding.

1. When I create a transaction is it broadcasted to the network and a bunch of nodes accept it or is it broadcasted to one specific node - I chose beforehand - which broadcasts this to other nodes ?

2. A contract deployment is also just a transaction so it should work the same way?

3. Why do I need Alchemy or similar providers to deploy a contract on the testnet? Isn't it possible to just connect to the Rinkeby or any other testnet? Is it because I have to specify an entry-point like a node?

4. Does this mean metamask has standard nodes it automatically connects to?

I know these are some very basic questions, still I am looking forward to getting your responses!

[krakxn]

The category should be Q&A for questions, and hence should be changed for others w/ similar doubts to refer to the answer.

1. Before reading this point further, refer to Mempools.

Partially yes, it is broadcasted to some extent for "preparation"; whereas when the block is mined, it is broadcasted to a greater extent for verification of the block. So, for a txn which has indeed been mined—i.e. the latter—yes.

Put simply, txns are "prepared" beforehand and therefore are unconfirmed txns. Txns are only confirmed when they are included in the blockchain, i.e they are mined (passed through). So, when the miner is including txns to be in the block, they are always capitalistic and will take on txns which yield the highest profits. Consequently, they pick such txns from the mempool to be included in the block they will mine.

3. A contract is essentially an account—i.e. public keys (put simply, account's address)—and the only difference between an externally-owned-account (EOA) and a contract is that the latter has logic (code) implemented whenever messages (transactions) are used to interact with it; whereas the former does not have any logic involved.

4. The JSON-RPC API is a popular method for interacting with Ethereum and is available in all major Ethereum node implementations (e.g. Geth and Parity) as well as many third-party web services (e.g. INFURA)

These third-party web services are very convenient as their APIs provide simplistic connections to these networks, and hence saves time and is productive. Of course, you can decide to not use them (similar to Hardhat, you can create your own test-environment), but you will have to do everything by yourself.

5. MetaMask is just a hot wallet for transactions and connections to blockchain-specific websites; it is not "connecting to nodes".

[clisterX]

First of all thanks for thte response!

However there is still one question. Can I directly connect to the Rinkeby-testnet and would this be the right URL: https://rinkeby.infura.io/v3/ ?

[krakxn]

No, you need your API key from Infura in this case which is in the same dashboard.

So, it will be something like this https://rinkeby.infura.io/v3/xyzapikey

[clisterX]

I guess to be able to do this, I would have to create an account at Infura or run my own node.

Feels very centralised, I hope this will change.

[krakxn]

That is correct.

True, somewhat. Just in case: Ankr and Pokt Network are some of the prominent decentralized node providers for now.